This invention relates to devices for imprinting identifying characters on exposed X-ray film, and more specifically to devices having indicia constructed of X-ray shielding material and which are self-adhering to any structure interposed between the source of X-rays and the X-ray film.
As is well known, certain materials, e.g. lead, are impermeable or opaque to X-rays. If such material is placed between the source of X-rays and the unexposed X-ray film, the film will upon exposure reveal a clear or transparent mark in the position where the X-ray shielding material was located.
It is often desirable to provide permanent identifying marks or characters, e.g. numbers, letters, and other symbols, on the exposed X-ray film. This practice of applying identifying markings on exposed X-ray film is both common and necessary in the medical field. In many instances, if an X-ray is taken, without the use of identifying characters, of a portion of a patient's body, the X-ray is often useless. Because exposed X-ray film is translucent to light, one side of the exposed film is the mirror image of the other side. For example, if an X-ray is taken of a patient's right hand, it would not be possible without detailed examination to determine whether that exposure was of the right or left hand unless there was a permanent record marked on the exposed X-ray film.
There are no commercially available reusable devices for applying identifying characters to exposed X-ray film. In conventional practice, the X-ray film is placed into an X-ray transparent or permeable film cassette in a dark room. The cassette is then taken out of the dark room and placed into a holder aligned with the X-ray source. When it is desired to make a permanent record on the exposed X-ray film of certain characters, e.g. "right," "anterior," "oblique," or any other type of identifying symbol, lead indicia are placed on the cassette and taped thereto, usually by adhesive tape which is readily available in hospitals and doctors' offices.
This conventional practice provides several disadvantages, the most obvious of which is that after the tape has been placed over the lead indicia and secured to the cassette, it is not possible to read the character that has been taped to the cassette. Accordingly, mistakes are frequently made which often lead to disastrous results when the exposed X-ray is then examined with improper markings on it. Another disadvantage of the conventional practice is that it is both time consuming and difficult to hold the lead indicia onto the normally vertically aligned cassette while the adhesive tape is cut and placed over the lead indicia. Furthermore, it is not possible to place multiple indicia in straight alignment with one another, for example when it is desired to spell particular words, because of the overlapping adhesive tape required for each individual letter.
U.S. Pat. Nos. 4,015,352 and 2,069,286 disclose self-adhesive indicia. U.S. Pat. No. 3,453,761 discloses three-dimensional plastic indicia which may be secured to a surface by pressure-sensitive adhesive.